Dynamoelectric machine brush rigging



July 13, 1943.V P. B. SHAFFER I 2,324,327

DYNAMO-ELECTRIC MACHINE BRUSH RIGGING Filed OCb. 25, 1942 Inventor: Paul B. Shaffer,

Patented July 13, 1943 DYNAMOELECTRIC MACHINE BRUSH RIGGIN G Paul B. Shaffer, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application October 23, 1942, Serial No. 463,089

(Cl. YY1-323) 11 Claims.

My invention relates to brush riggings and more particularly to a brush rigging adapted to be used with a dynamo-electric machine which -rotates bodily.

An object of my invention is to provide an .improved brush rigging.

Another object of my invention is to provide an improved brush rigging for a bodily rotatable vdynamo-electric machine wherein centrifugal -force has substantially no effect o-n the pressure of the brush on an electrical contact member of the machine.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my -invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawing, Fig. 1 is a side elevational view 'of a brush rigging provided with an embodiment of my invention with a substantially unused electrical contact brush therein; Fig. 2 is a side elevational View of the arrangement shown in Fig. 1,

partly broken away, illustrating a substantially worn-out contact brush; Fig. 3 is an end view,

partly broken away, of the construction shown in Figs.` 1 and 2 taken along line 3 3 of Fig. l;

Fig. 4 is an outline illustration of the brush holder shown in Figs. 1 to 3 illustrating the forces acting thereon due to the machine rotating bodily about its axis; and Fig. 5 is a side elevational View of the brush rigging shown in Fig. l.

Referring to the drawing, I have shown a brush rigging adapted to be used with a bodily rotatable dynamo-electric machine having an electrical contact commutator member I0 to which the brush relative to the current collector I0. This result is obtained by pivotally supporting an electrical contact brush |I about an axis substantially at right angles to the action of centrifugal force, that is, about va pivotal support, the axis of which is substantially .parallel to the action of centrifugal force on the brush holder. My improved brush rigging includes a brush holder having two arms |2 and I3 extending from a hub I4. The arm I2 is formed at the outer end `thereof as a brush support l5 in which the brush I is arranged and to which the brush is secured by a screw I. The brush holder arm I3 is formed `at its outer end with a balance weight |'I such -that the arm I2, together with its brush Il and securing vscrew I6, has substantially the same weight as the arm I3 and its balance weight I'I. Furthermore, the masses of the two arms and associated elements are such that the center of gravity I8 of the arm I2 and its associated equipment is located at a distance a from the center the center of gravity of the brush holder. The brush holder hub I4 is rotatably supported about a pivot pin 2| having an axis substantially at right angles to the axis of rotation of the dy# namo-electric machine, and this pivot pin is arranged to provide a pivotal support for the brush holder arms substantially through the center of gravity I9 of the brush holder, providing substantially equal moments for each of the arms I2 and E3 about a point on the axis of the pivot pin I4 due to centrifugal forces Fa acting on the arm I2 and Fs on the arm I3 when the machine rotates bodily. As shown in Fig. 4, the center of gravity of the brush holder will shift slightly as the brush II becomes worn, and moves from |91 to |92 for its extreme positions. This, however, is a relatively small change and has substantially no effect on the operation of the device. These centrifugal forces Fs and Ft act substantially parallel to the axis of the pin and through moment arms a and b which are substantially equal. Since the forces Fa and Fb have moments in opposite directions about the axis of the pin 2|, there is substantially no resultant moment tending to rotate the brush holder at right angles lto the axis of the pin 2| due to centrifugal force.

'by an end plate 26 secured to the housing 25 by a pair of screws 21. The bearing housing 25 is formed in a supporting bracket 28 and provides a journal bearing surface 29 for rotatably supporting the thrust plate end 22 of the pivot supporting pin 2|. The other end of the pivot pin 2| is supported in a journal bearing element 30, also formed on the supporting bracket 28. With this construction, the brush holder is free to pivot about the axis of the pin 2| substantially transversely of the axis of rotation of the machine and towards or away from the current collecting commutator l0. In order to provide the desired biasing pressure of the contact brush I into engagement with the commutator Ill, a biasing coil spring 3| is arranged about the central portion of the pivot pin 2| with one end 32 thereof arranged in engagement with the supporting bracket 28 and the other end 33 thereof arranged in engagement with the contact brush carrying arm I2. This spring 3| acts in a direction at right angles to the action of centrifugal force on the brush holder and, therefore, is substantially unaffected by centrifugal force resulting from the rotation of the machine bodily about its axis. The bearing bracket 28 may be suitably supported on the end shield 34 of the machine yby securing bolts 35. With this construction, substantially all of the thrust on the brush holder resulting from the action of centrifugal force from the rotation of the brush rigging with the rotation of the machine is transmitted to antifriction bearings 23 along the axis of the pivotal support of the brush holder and has substantially no effect in the direction in which the contact kbrush is biased towards the current collector I0.

vWhile I have illustrated and described a particular embodiment of my invention, modiiications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my inventi-on is not to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by yLetters Patent of the United States is: l. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms extending substantially transversely of the axis of rotation of said machine, one of said arms being formed to hold an electrical contact brush element, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamoelectric machine arranged to provide a pivotal support for said brush holder arms with substantially equal moments for each of said arms about a point on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, and means including a supporting bracket for rotatably supporting said pivot pin.

2. A brush rigging for an electrical contact member of a bodily rotatable dynamo-electric machine including a brush holder having two arms extending substantially transversely of the axis of rotation of said machine, one of said arms being formed to hold an electrical contact brush element, and a pivot support having an axis substantially at right angles to the axis of rotation of'said dynamo-electric machine and to said arms and being arranged to support said brush holder arms with substantially equal moments for each of said arms about a point substantially on the axis of said lsupport due to centrifugal force acting on said arms by the rotation of said machine.

3, A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms extending substantially transversely of the axis of rotation of said machine, one of said arms being formed to hold an electrical contact brush element, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamoelectric machine and to said arms and being arranged to provide a pivotal support for said brush holder arms with substantially equal moments for each of said arms about a point substantially on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, and means for supporting said pivot pin.

4. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms, one of said arms being formed to hold an electrical contact brush element, the other of said arms being provided with a weight thereon, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamo-electric machine arranged to provide a pivotal support for said brush holder arms substantially through the center of gravity of said brush holder with substantially equal moments for each of said arms about a point substantially on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, means for supporting said pivot pin, and means for biasing said contact element carrying arm toward an elec.- trical contact member of said dynamo-electric machine.

5. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms, one of said arms being formed to hold an electrical contact brush element, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamo-electric machine arranged to provide a pivotal support for said brush holder arms with substantially equal moments for each of said arms about a point on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, a mounting for said brush holder including means for transmitting axial thrust due to centrifugal force from said brush holder to said mounting, means for rotatably supporting said pivot pin on said supporting bracket, and means for biasing said contact element carrying arm toward an electrical contact member of said dynamo-electric machine.

6. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms, one of said arms being formed to hold an electrical contact brush element, the other of said arms being provided with a weight thereon, means for providing a pivotal support for said brush holder arms substantially through the center of gravity of said brush holder with substantially equal moments for each of said arms about a point on the axis of said support and substantially at right angles to the axis of rotation of said machine due t0 centrifugal force acting on said arms in a direction substantially parallel to the `axis of said support, a mounting for said brush holder in.- cluding means for transmitting axial thrust due to centrifugal force from said brush holder, to said mounting, and means for biasing said contact`element carrying arm toward an electrical contact member of said dynamo-electric machine.

7. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms extending substantially transversely of the axis of rotation of said machine, one oi said arms being formed to hold an electrical contact brush element, a pivot pin having an axis substantially at right angles to the axis of rotation oi said dynamo-electric machine and to said arms and being arranged to provide a pivotal support for said brush holder arms with substantially equal moments' for each of said arms about a point substantially on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, a mounting for said brush holder including a supporting bracket having a bearing housing and a plurality of anti-friction ball bearings in said bearing housing, and means on said pin for transmitting axial thrust due to centrifugal force from said brush holder to said pin and from said pin to said anti-friction bearing.

8. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms extending substantially transversely of the axis of rotation or" said machine, one of said arms being formed to hold an electrical contact brush element, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamoelectric machine arranged to provide a pivotal support for said brush holder arms with substantially equal moments for each of said arms about a point on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, a mounting for said brush holder including a supporting bracket having a bearing housing and a plurality of antifriction ball bearings in said bearing housing, means on said pin for transmitting axial thrust due to centrifugal force from said brush holder to said pin and from said pin to said anti-friction bearing, and means for rotatably supporting said pivot pin on said supporting bracket.

9. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms, one of said arms being formed to hold an electrical contact brush element, the other of said arms being provided with a weight thereon, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamo-electric machine arranged to provide a pivotal support for said brush holder arms substantially through the center of gravity of said brush holder with substantially equal moments for each of said arms about a point on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, a mounting for said brush holder including means for transmitting axial thrust due to centrifugal force from said brush holder to said mounting, means for rotatably supporting said pivot pin on said mounting, and means for biasing said contact element carrying arm toward an electrical contact member of said dynamo-electric machine.

l0. A brush rigging for an electrical contact member of a bodily rotatable dynamo-electric machine including a brush holder having two arms, one of said arms being formed to hold an electrical contact brush element, the other of said arms being provided with a weight thereon, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamoelectric machine arranged tc provide pivotal support for said brush holder arms with substantially equal moments for each of said arms about a point substantially on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, a mounting for said brush holder including a supporting bracket having a bearing housing and a plurality of anti-friction ball bearings in said bearing housing, means on said pin for transmitting axial thrust due to centrifugal force from said brush holder to said pin and from said pin to said anti-friction bearing, means for rotatably supporting said pivot pin on said supporting bracket, means for biasing said contact element carrying arm toward an electrical contact member of said dynamo-electric machine.

l1. A brush rigging for an electrical contact member of a dynamo-electric machine including a brush holder having two arms, one of said arms being formed to hold an electrical contact brush element, the other of said arms being provided with a weight thereon, a pivot pin having an axis substantially at right angles to the axis of rotation of said dynamo-electric machine arranged t0 provide a pivotal support for said brush holder arms substantially through the center of gravity of said brush holder with substantially equal moments for each of said arms about a point on the axis of said pin due to centrifugal force acting on said arms in a direction substantially parallel to said pin, a mounting for said brush holder including a supporting bracket having a bearing housing and a plurality of anti-friction ball bearings in said bearing housing, means including a thrust plate element on said pin for transmitting axial thrust due to `centrifugal force from said brush holder to said pin and from said pin te said anti-friction bearing, means including a journal bearing for rotatably supporting said pivot pin on said supporting bracket, and means including a biasing coil spring arranged about said pivot pin in engagement with said bracket and with said brush holder for biasing said contact element carrying arm toward an electrical contact member of said dynamo-electric machine.

PAUL B. SHAFFER. 

